This application requests support for a new multidepartmental predoctoral training program in virology at Yale University. Yale has recently established a new academic section of Microbial Pathogenesis and a new Ph.D. program in Microbiology, and several energetic new faculty members in virology have been recruited. In conjunction with existing strengths at Yale in virology, genetics, structural biology and related areas, we have now attained the critical mass to sustain a vigorous Ph.D. training program in virology. A great strength of this program is its faculty, which in aggregate provides expertise in virtually every aspect of virology. Many of the faculty are outstanding investigators with distinguished records of research accomplishments and training experience. The goal of this program is to train scientists so that they can carry out independent, innovative research careers in academia, industry, and government. They will receive didactic and laboratory training in methods of growing viruses, analyzing the virus life cycle and viral proteins, and characterizing the interactions between viruses and their host ceils. Stipend and tuition support is requested for nine slots, enough to support three entering students in each class for three years. Trainees with research experience and high potential will be admitted through the Combined Graduate Program in the Biomedical and Biological Sciences. Plans are in place to recruit minority applicants to this training program. Trainees must fulfill a variety of requirements including completion of one and one-half years of course work, research rotations, a qualifying examination, a teaching requirement, a course in ethics, and thesis research. Most students will complete their studies in five to six years and go on to postdoctoral research positions. Graduates of this program will be ideally suited to carryout basic and applied research on viruses, virus-cell interactions, and viral diseases, and will contribute to the nation's response to the threat of viruses as bioterrorist weapons.